Search Results (49)

The scientific literature lacks sufficient data on the transport of various toxic pollutants by polymer particles. Investigating how the structure of microplastic particles formed during the degradation of polymeric materials affects pollutant sorption processes will improve our ability to predict environmental behavior. General-purpose polystyrene, expanded polystyrene, ABS plastic (acrylonitrile–butadiene–styrene) and crosslinked polystyrene are produced on an industrial scale. Copolymers of styrene with divinylbenzene are used on a large scale as sorbents for gel permeation chromatography (Styragel brand sorbents), in the production of catalysts on a polymer substrate or ion-exchange resins. In this study, non-spherical, crosslinked polystyrene microparticles with varying polystyrene chain packing densities were used as model microplastic particles representative of crosslinked polystyrene. It was shown that the adsorption of a hazardous chemical rhodamine B was influenced by both the packing density of the polystyrene chains and the presence of ionic functional groups, i.e., the “degree of aging” of the microplastic particles. The sorption capacities of these model microparticles were compared with those of natural origin (silicon dioxide, quartz powder, and microcrystalline cellulose). A viability assay using HEK293 and HeLa cell lines exposed to leachates from both pristine and rhodamine B-loaded microparticles revealed that all unmodified microparticles, regardless of their nature, exhibited no cytotoxicity at concentrations up to 1000 μg/mL. In contrast, microparticles with adsorbed rhodamine B significantly reduced cell viability to 20–40% at concentrations of 100 μg/mL. Full article

Rising plastic production worldwide is contributing to the increasing amounts of micro- and nanoplastics found in the environment. The consumption of microplastics by humans is plausible due to the presence of plastic particles in various food commodities, yet the potential impact of microplastics on human health remains unknown. Several studies have detected microplastics in human tissues and research using mammalian in vivo and in vitro models have noted toxicity after exposure to microplastics. Using both mono- and co-culture liver cell models, we assessed the impact of environmentally relevant, cryo-milled plastic particles on hepatotoxicity. We observed that only cryo-milled polyethylene terephthalate and polystyrene altered mitochondrial energy metabolism, while the other plastic particles did not. The pristine, spherical polystyrene particles were taken up at all sizes and cryo-milled polystyrene was taken up by cells. Evidently, polymer type and shape play a critical role in hepatotoxicity. Further research is required to fully elucidate the effect the physiochemical properties of plastic particles may have on toxicity. Full article

Microplastics (MPs) are widespread worldwide and have become a significant environmental problem due to their durability and the large quantities that enter ecosystems. As the global spread of microplastic pollution continues, the Armenian gull (Larus armenicus) in the Lake Van Basin has emerged as an important bioindicator. This study highlights the widespread impact of human-generated waste on natural habitats by detecting the presence of microplastics in gull feces using a non-invasive, polymer-supported method. Methods: The study was conducted between 10 May 2024 and 26 April 2025. A total of 480 fecal samples were analyzed from four stations with different characteristics and exposed to various anthropogenic effects. Instead of individual-level statistical inference, we performed temporal comparisons descriptively at the composite level. Results: We categorized suspected MPs by type, shape, size, and color, using FTIR to confirm the polymer identity of a representative subset (>300 µm; ~20%) and SEM–EDX to examine particle surfaces. A total of 8197 MP particles were observed in the feces collected from the stations. The most frequently observed MP type, size, shape and color were fiber (32.6%), 100–300 µm (30.8%), spherical (29.2%) and brown (18.4%), respectively. The chemical structures of all examined MPs were polyethylene (PE) (42.6%), polystyrene (PS) (28.38%) and polyethylene terephthalate (PET) (8.5%). SEM-EDX confirmed that the microplastics are polymers by showing their degraded surface and carbon/oxygen ratio. Conclusions: Identifying polymer species in ingested plastics is valuable for future studies, as the results can be used to assess the relationship between microplastics. Full article

Microplastics (MP) have been found not only in the environment but also in living beings, including humans. As an initial step in MP detection, a method is proposed to measure the effective refractive index of a solution containing 5 µm diameter spherical polystyrene particles (SPSP) in distilled water, based on the surface plasmon resonance (SPR) technique and Mie scattering theory. The reflectances of the samples are obtained with their resonance angles and depths that must be normalized and adjusted according to the reference of the air and the distilled water, to subsequently find their effective refraction index corresponding to the Mie scattering theory. The system has an optical sensor with a Kretschmann–Raether configuration, consisting of a semicircular prism, a thin gold film, and a glass cell for solution samples with different concentrations (0.00, 0.20, 0.05, 0.50, and 1.00%). The experimental result provided a good linear fit with an R² = 0.9856 and a sensitivity of 7.2863 × ${10}^{-5}$ RIU/% (refractive index unit per percentage of fill fraction). The limits of detection (LOD) and limit of quantification (LOQ) were determined to be 0.001% and 0.0035%, respectively. The developed optomechatronic system and its applications based on the SPR and Scattering enabled the effective measurement of the refractive index and concentration of solutions containing 5 µm diameter SPSP in distilled water. Full article

Microplastics are widely present in the environment, and their potential risks to human health have attracted increasing attention. Research on microplastics has exhibited exponential growth since 2014, with a fast-growing focus on human health risks. Keyword co-occurrence networks indicate a research shift from environmental pollution toward human exposure and health effects. Additionally, Trend Factor analysis reveals emerging research topics such as reproductive toxicity, neurotoxicity, and impacts on gut microbiota. This meta-analysis included 125 studies comprising 2977 data samples. The results demonstrated that cytotoxicity in experimental systems was primarily concentrated in Grade I (non-toxic, 62.8%) and Grade II (mildly toxic, 27.6%). Notably, inhibitory effects on cells were significantly enhanced when microplastic concentrations exceeded 40 μg/mL or particle sizes were smaller than 0.02 μm. The Gradient Boosting Decision Tree (GBDT) model was applied to predict cell viability, achieving an R² value of 0.737 for the test set and a classification accuracy of 81.5%. Furthermore, reproductive- and circulatory-system cells exhibited the highest sensitivity to microplastics, whereas connective-tissue cells had the lowest survival rates. The study also identified an overuse of polystyrene (PS) polymers and spherical particles in experimental designs, deviating from realistic exposure scenarios. Full article

Micro- and nanoplastics (NMPs) have recently gained attention as one of the most pervasive and potentially dangerous environmental pollutants. An increasing number of studies have explored the presence and potential health consequences of NMPs exposure, leading to calls for techniques to assess their bioaccumulation. Significant gaps that remain in this growing field of research are methodologies to quantify discrete particle counts of NMPs below 5 μm in size and evaluate the recovery rate of such methods to ensure accuracy and comparability across studies. To address these gaps, we aimed to develop a high-throughput protocol for the extraction, isolation, and quantification of a 1:1 volume mixture of 2 and 0.1 μm pristine fluorescently labeled spherical polystyrene NMPs (PS-NMPs) from mouse tissue, and to determine recovery rates of both sizes to assess the success of the methodology. We found that we were able to successfully recover 85% of 2 μm NMPs and 30% of 0.1 μm NMPs, and that this workflow could be applied to tissues from mice experimentally exposed to a concentration gradient of PS-NMPs to detect differences in accumulation. This methodology is the first to attempt a continuous workflow to assess particle counts of both micro- and nanoplastics from biological tissues, including calculations of recovery rates, and we anticipate that the workflow described here may be applied and modified in future studies to answer outstanding questions regarding the accumulation of small NMPs that may not be addressed with traditional techniques. Additionally, in identifying the significant differences in recovery rates for micro- versus nanoplastics, we highlight the considerations that must be taken into account for nanoplastics that are often not discussed within the NMPs literature. Full article

Simulative and experimental studies were carried out to address multi-dimensional particle fractionation of non-biological particles according to size, shape, and density inside a high-throughput DLD array. Density sensitive separation was achieved for melamine and polystyrene particles at a diameter of 5 µm at a Reynolds number (Re) of 82, corresponding to an overall flow rate of 11.3 mL/min. This process is very sensitive, as no fractionation occurred for Re = 85 (11.7 mL/min). For the first time, the fractionation of elliptical polystyrene particles (5 × 10 µm) at Re > 1 was investigated up to Re = 80 (11 mL/min). A separation of elliptical particles from spherical melamine particles (5 µm) was observed in single experiments at all investigated Reynolds numbers. However, the separation is not reliably repeatable due to partial clogging of ellipsoidal particles along the posts. In addition, higher concentrations of polydisperse silica suspensions were experimentally investigated by using polydisperse silica particles at concentrations up to 0.4% (m/V) up to Re = 80 (20 mL/min). The separation size generally decreased with increasing Reynolds number and increased with increasing concentration. Separation efficiency decreased with increasing concentration, independent of the Reynolds number. In order to investigate the material-dependent separation in a contactless dielectrophoresis system (cDEP), the resolved CFD-DEM software was extended to calculate dielectrophoretic forces on particles. With this, the second stage of a serial-combined DLD-DEP system was simulated, showing good separation at lower flow rates. For these systems, different fabrication methods to minimize the distance between the electrodes and the fluid as well as the requirement to withstand high-throughput applications, were investigated. Full article

Mechanically driven cellular preference for drug carriers can enhance selectivity in cancer therapy, underscoring the importance of understanding the physical aspects of particle uptake. In this study, it was hypothesized that elongated particles might be preferentially taken up by deformable, aggressive cancer cells compared to normal cells. Two film-stretching methods were tested for 0.8–2.4 μm polystyrene (PS) particles: one based on solubility in organic solvents and the other on heat-induced softening. The heat-induced method produced more homogenous particle batches, with a standard deviation in the particle aspect ratio of 0.42 compared to 0.91 in the solvent-based method. The ability of cells to engulf elongated PS particles versus spherical particles was assessed in two subsets of human melanoma A375 cells. In the more aggressive cancer cell subset (A375+), uptake of elongated PS particles increased by 10% compared to spherical particles. In contrast, the less aggressive subset (A375−) showed a 25% decrease in uptake of elongated particles. This resulted in an uptake ratio between A375+ and A375− that was 1.5 times higher for elongated PS particles than for spherical ones. To further demonstrate relevance to drug delivery, elongated paclitaxel-loaded biodegradable, slow-releasing poly(lactic-co-glycolic) acid (PLGA) particles were synthesized. No significant difference in cytotoxic effect was observed between A375+ and A375− cells treated with spherical drug-loaded particles. However, treatment with ellipsoidal particles led to a significantly enhanced cytotoxic effect in aggressive cells compared to less aggressive cells. These findings present promising directions for tailored cancer drug delivery and demonstrate the importance of particle physical properties in cellular uptake and drug delivery mechanisms. Full article

Model spherical polystyrene particles are studied to understand the interactions of microplastics with organic pollutants. Analysis of the experimental results presented in the literature is complicated since researchers use different types and concentrations of particles, durations of tests, etc. In addition, there is little information on the effect of the structure of the surface layer of polystyrene particles on the processes under study, and the question of the effect of the shape of polystyrene particles remains open. Here, we present the first results of a model experiment to study the effect of the shape and structure of the surface layer of polystyrene microspheres and non-spherical particles of 2 to 5 μm in size on the sorption properties in relation to model molecules of rhodamine B as a model organic pollutant. The properties of both the initial model polystyrene particles and the modified ones were studied by optical, transmission electron, and atomic force microscopy, as well as using the Brunauer–Emmett–Teller method (BET). The sorption process was studied by spectrophotometry, and the analysis of sorption curves was carried out using the Langmuir model. It is shown that the shape of polystyrene model particles does not have a significant effect on the sorption capacity. At the same time, the sorption processes of rhodamine B molecules are determined by the structure of the surface layer, which can be changed, for example, by exposing the polystyrene microspheres to N,N′-dimethylformamide. Full article

Global consumption has led to an increased and persistent plastic pollution in the aquatic environments. Due to their small size, plastic particles are omnipresent, affecting aquatic biota. Polystyrene is a synthetic polymer and one of the most widely used plastics. Its accumulation in the environment endangers the health of aquatic organisms. This study aims to investigate the acute (7 days) and chronic (75 days) toxicity of spherical polystyrene particles (20, 200, 430 µm) on Cyprinus carpio fish using OECD methodology. No mortality or behavioral changes were recorded after acute or chronic tests conducted on 1, 10, 100 mg/L polystyrene particles. Polystyrene showed bioavailability mainly through ingestion with food, causing weight loss in fish. Fish lots exposed to the polystyrene mix (particle sizes of 20, 200, 430 µm and 1.2 mg PS/L total concentration) showed changes in physiological indices but without major significance compared to control lots. After 75 days of chronic exposure of fish to a mix of polystyrene particles, organs were collected for sub-lethal effect investigation. Polystyrene was found to cause oxidative stress in fish organs. A very significant increase in the activity of the enzymes catalase and glutathione reductase, correlated with lipid peroxidation in gills, were observed. In the liver, catalase and glutathione S transferase activity increased, but there were no lipid peroxidation effects. Also, alanine transferase and aspartate transferase activity showed significant changes. Regarding the vitellogenesis initiated in the liver, vitellogenin activity increased by 40%. EROD activity saw a 20% increase compared to control fish, indicating stress enzyme expression. Instead, acetylcholinesterase showed significant inhibition (>80%) in the brain and muscle. The protein profile showed new stress protein expression compared to the control in the gills and liver. Based on the results of our study, the introduction of new regulations monitoring the accumulation of microplastics in surface water is an urgent matter. Full article

Statistical analysis of the properties of single microparticles, such as cells, bacteria or plastic slivers, has attracted increasing interest in recent years. In this regard, field flow cytometry is considered the gold standard technique, but commercially available instruments are bulky, expensive, and not suitable for use in point-of-care (PoC) testing. Microfluidic flow cytometers, on the other hand, are small, cheap and can be used for on-site analyses. However, in order to detect small particles, they require complex geometries and the aid of external optical components. To overcome these limitations, here, we present an opto-fluidic flow cytometer with an integrated 3D in-plane spherical mirror for enhanced optical signal collection. As a result, the signal-to-noise ratio is increased by a factor of six, enabling the detection of particle sizes down to 1.5 µm. The proposed optofluidic detection scheme enables the simultaneous collection of particle fluorescence and scattering using a single optical fiber, which is crucial to easily distinguishing particle populations with different optical properties. The devices have been fully characterized using fluorescent polystyrene beads of different sizes. As a proof of concept for potential real-world applications, signals from fluorescent HEK cells and Escherichia coli bacteria were analyzed. Full article

The detection and quantification of micro(nano)plastics in the marine environment are essential requirements to understand the full impacts of plastic pollution on the ecosystem and human health. Here, static light scattering (SLS) and dynamic (DLS) light scattering techniques are assessed for their capacity to detect colloidal particles with diameters between d = 0.1 and 0.8 µm at very low concentrations in seawater. The detection limit of the apparatus was determined using model monodisperse spherical polystyrene latex particles with diameters of 0.2 µm and 0.5 µm. It is shown that the concentration and size of colloids can be determined down to about 10⁻⁶ g/L. Light scattering measurements on seawater obtained from different locations in Western Europe show that colloidal particles were detected with DLS in seawater filtered through 0.8 µm pore size filters. The concentration of these particles was not higher than 1 µg/L, with an average diameter of about 0.6 µm. We stress that these particles are not necessarily plastic. No particles were detected after filtration through 0.45 µm pore size filters. Full article

Organic–inorganic nanocomposite particles, possessing defined morphologies, represent the next frontier in advanced materials due to their superior collective performance. In this pursuit of efficient preparation of composite nanoparticles, a series of diblock polymers polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) were initially synthesized using the Living Anionic Polymerization-Induced Self-Assembly (LAP PISA) technique. Subsequently, the tert-butyl group on the tert-butyl acrylate (tBA) monomer unit in the diblock copolymer, yielded from the LAP PISA process, was subjected to hydrolysis using trifluoroacetic acid (CF₃COOH), transforming it into carboxyl groups. This resulted in the formation of polystyrene-block-poly(acrylic acid) (PS-b-PAA) nano-self-assembled particles of various morphologies. The pre-hydrolysis diblock copolymer PS-b-PtBA produced nano-self-assembled particles of irregular shapes, whereas post-hydrolysis regular spherical and worm-like nano-self-assembled particles were generated. Utilizing PS-b-PAA nano-self-assembled particles that containing carboxyl groups as polymer templates, Fe₃O₄ was integrated into the core region of the nano-self-assembled particles. This was achieved based on the complexation between the carboxyl groups on the PAA segments and the metal precursors, facilitating the successful synthesis of organic–inorganic composite nanoparticles with Fe₃O₄ as the core and PS as the shell. These magnetic nanoparticles hold potential applications as functional fillers in the plastic and rubber sectors. Full article

Nanoplastics have gradually become a concern due to the wide use of plastics. Nanoplastics in aqueous phase can be exposed to users through water supply networks and cannot be efficiently removed by conventional water treatment processes. This work studied the degradation of polystyrene nanoplastics (PS-NP) by two commonly used advanced oxidation systems: UV/NaClO and UV/peroxymonosulfate (PMS). Results showed that almost no turbidity was detected in the PS-NP solution (5.00 mg/L) after treated by both UV/NaClO and UV/PMS for 360 min, suggesting the excellent turbidity removal ability. Yet, scanning electron microscope (SEM) and total organic carbon (TOC) removal tests demonstrated that PS-NP could not be completely degraded by UV/NaClO. The mineralization rate using UV/NaClO was only 7.00% even when the NaClO concentration increased to 5.00 mM, and many PS-NP particles could still be observed in SEM images. By contrast, the mineralization rate reached 63.90% in the UV/PMS system under the identical experimental conditions, and no spherical particles appeared in the SEM results. Density functional theory (DFT) calculations revealed that the different reaction sites and energy barriers of SO₄^•− and ^•Cl on PS-NP resulted in the differences in mineralization rates and degradation intermediates. The degradation pathway of PS-NP by UV/NaClO and UV/PMS was proposed accordingly. Additionally, the intermediates toxicity evaluation by a luminescent bacteria test showed that the inhibition rate in the UV/NaClO system (2.97%) was not markedly different from that in the control group without any treatment (1.98%); while that in UV/PMS system increased sharply to 98.19%. This work demonstrated that UV/PMS was more effective in PS-NP degradation than UV/NaClO, and the chemical risks of degradation intermediates were non-negligible. Full article

Non-spherical polymer nanoparticles (NPs) have gained attention in various fields, but their fabrication remains challenging. In this study, we present a simple protocol for synthesizing partially etched polystyrene (PS) nanoparticles through emulsion polymerization and chemical etching. By adjusting the degree of crosslinking, we selectively dissolve the weakly crosslinked portions of the particles, resulting in partially etched PS NPs with increased surface area. These partially etched NPs are evaluated for their use as solid surfactants in Pickering emulsions, where they demonstrate significantly improved emulsion stability compared to intact spherical NPs. Our results contribute to the field of nanoparticle shape control and provide insights into developing novel materials for various applications, particularly in the area of solid surfactant usage. Additionally, the importance of conducting cellular toxicity studies using these partially etched NPs for future work is also emphasized. Full article